My Chevy Bolt Is on Third Battery Pack: Here’s Why
insideevs.com
insideevs.com
Also, Panasonic manufactures most of these battery cells anyway (including Tesla's). Tesla uses those cells to construct the battery pack. The incumbents generally farm battery pack construction out to Panasonic or other specialized battery makers.
If a single cell out of hundreds is bad, the circuitry should be able to wait till that cell is depleted, and then temporarily (or even permanently!) take it out of the circuit, allowing the remaining capacity in the other cells to be used.